Physicochemical wastewater treatment techniques

Physico-chemical water treatment techniques

Often, industrial wastewater does not meet the required standards (e.g. Vlarem) for discharge – definitely not for reuse. First of all, the toxic components must be removed from the wastewater flow. There are numerous physico-chemical water purification techniques for this purpose.

These techniques are used for the removal of:

  • Heavy metals
  • Suspended matter and emulsifying organic particles
  • Hardly degradable, non-polar organic substances
  • Oils and fats
  • Organic and inorganic components (e.g. phosphorus, salts)
  • Toxic pollutants

The physico-chemical water treatment techniques are used as pre-treatment, final treatment or specific treatment for reuse as process water.

Which physicochemical techniques are used in water treatment?

The type of water treatment depends primarily on the size of the particles present in the wastewater. Solid particles that are visible to the naked eye can be removed in three, relatively easy ways. These particles are removed with filtration, flotation or sedimentation.

The fine suspended particles (< 1 µm) are more difficult to remove. These particles can only be removed by means of physical-chemical water treatment techniques. 

Our working method consists of performing lab tests with the wastewater. In this way, it can be determined in advance which techniques are most suitable.

  • flocculation
  • coagulation
  • flotation
  • neutralization
  • electroflotation
  • membrane technology – membrane filtration
  • NH3 stripper-absorbers, sludge treatment

Flotation: separation of suspended solids, oils, fats and undissolved particles. This technique can be used as pretreatment for further purification or as sole treatment of the water. The most commonly used flotation technique is Dissolved Air Flotation (DAF), in which air is dissolved under pressure in the water to be treated. The very fine bubbles bind with the floc particles in the water. The floc particles rise to the water surface and form a floating layer. The floating layer is scraped off and collected in a container. The sludge can then be further thickened and/or dewatered.

The great advantage of this type of installation is that it can be fully automated and is therefore very low maintenance.

Neutralization: wastewater is neutralized (pH +- 7) to make it suitable for further degradation in a biological wastewater treatment plant or to meet discharge standards.

Neutralization techniques involve adding chemicals to the wastewater. Some examples of neutralization units can be found below. It is a fairly compact set of storage and reaction tanks with the necessary dosing and mixing equipment. In addition to neutralizations, the pH of wastewater can also be changed for other reasons: better control of chemical reaction rates, breaking of emulsions, conditioning, stabilization of raw wastewater, etc.

Neutralization is a technique applied to a wide variety of wastewaters. These types of installations are quite simple. Moreover, they can be fully automated and are therefore low maintenance. Due to the simple construction, the investment cost can also be kept low.

 

Membrane technology: deferrization, softening, demineralization using membranes, also water recovery.

Stripping: removal of NH3 with strippers (stripping towers) – absorbers.

scrubber
filter press for sludge dewatering

Sludge treatment: in many cases, sludge remains as a residual product after the physicochemical water treatment process. In most plants, the sludge is removed by third parties. Therefore, it is of economic importance to keep the volume of sludge as small as possible. One method of dewatering the sludge is the chamber filter press. Optionally, the presses can be equipped with a high-pressure spray system to clean the cakes.

 

Water treatment – physicochemical wastewater treatment plants – Integrated solutions

Whether it is a completely new installation, or the renovation or optimization of an existing installation, we offer you a correct solution, with an optimal price-quality ratio. Our installations are always seamlessly integrated into the existing situation of each production site. We aim for durable, maintenance-friendly and correctly dimensioned installations. In addition, we provide thorough training of the on-site maintenance staff to ensure that the wastewater treatment plant will continue to run smoothly in the long term. If despite this there are problems, we are always ready for a quick intervention.

 

Our expertise

Various companies from different sectors (food, feed, recycling, automotive, pharma, chemical, …) already made or are making use of our expertise for the construction of water treatment installations and/or air purification and odor control installations. For all the above-mentioned specializations, we can present one or more references.

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